1905.] Wheele?-, The Ants of New Jersey. 393 



genital valves of the male. For the sake of comparison I figure the 

 valves of guatemalensis (Fig. 4) and of the three species enumerated 

 from New Jersey (Figs, i to 3). The valves of two other North 

 American species (P. truest Wheeler and P. melanderi Wheeler) are 

 given in Psyche (June, 1903, pp. 104 and 107), and Emery (Beitrage, 

 etc., 1893, pi. xxii, Fig. 24) has figured the outer genital valves of 

 P. fulva Mayr. 



Lasius Fabr. 



58. L. niger Linn. var. americanus Emery. — Camden, River- 

 ton, and Anglesea (Viereck) ; Cape May (Phila. Acad.) ; Jamesburg 

 (Davis); Halifax, Lakehurst, and Fort Lee (Wheeler). 



This form passes in much of our entomological literature as L. 

 alienus, although Emery has given reasons for regarding it as dis- 

 tinct from the European form. It is not only the commonest of our 

 numerous species of Lasius but the most abundant of our ants, and 

 hence of all our insects. It occurs over the whole of North America 

 except the extreme southern and southwestern portions, from timber- 

 line on the highest mountains to the sands of the seashore. Even in 

 circumscribed localities it shows in its nesting sites great adaptability 

 to different physical conditions, from the damp rotten wood of dense 

 forests to the sandy soil of dry, sunny roads. Usually the workers liv- 

 ing in the latter stations are much paler in color than the woodland 

 forms and might be regarded as representing a distinct variety. The 

 nests are indifferently under bark, logs, or stones, in rotten wood or in 

 the soil. When in soil they are surmounted by small single or clustered 

 craters. Like all of our other species of the genus, L. niger var. 

 americanus is much given to cultivating root-coccids and root-aphids 

 in the chambers and galleries of its nests, but, with the exception of 

 the var. neoniger, it is the only one of our forms that is not exclu- 

 sively subterranean in its habits. It may often be seen visiting the 

 foliage of trees and bushes in search of Aphides and small insects. 

 Prof. A. S. Forbes 1 has shown that this insect is of considerable 

 economic importance on account of its noxious habit of cultivating 

 the root-aphids of maize, or Indian corn (Aphis maidiradicis) . His 

 observations are well worth quoting, as they throw light not only on 

 the habits of this and our other species of Lasius but also of other 

 aphicolous ants: 



" Seven kinds of ants have been found by us fulfilling the reaction 



' A Monograph of Insect Injuries to Indian Corn. Part I. Trans. Dep. Agr. 111., Springfield, 

 1894. 



